Electrolytic Hydrogen: A Future Technology for Energy Storage

-Falak Shah and Shival Trivedi

Storing electrical energy Pros and cons of techniques What is hydrolysis Why hydrolysis method Cobalt phosphate catalysis Hydrogen storage Hydrogen as a fuel Safety and limitations Practical Scenario

Contents

Two billion people on earth do not have electricity.

Global energy need driven by 3 billion low energy users in the non legacy world will roughly double by midcentury.

New R&D needed to provide the world with the “fast food” equivalent of energy systems.

Grid parity, fly-wheel, pumped water, compressed air,Li-ion batteries, ultracapacitors

Storing Electrical Energy

BATTERIES COMPRESSED AIR FLYWHEEL

Ultracapacitors Pumped water

Pros & Cons of Storage Techniques

High efficiencyEasy availability

Compact

Light Weight

High energy capacity

High Centrifugal force Not economical

Geological structure reliance Soil erosion

Largest capacity of electricityFast start-up

Less energy densityFluctuations in supply

When the input devices produce more energy than is required by the load, the excess energy is converted by an electrolyzer to electrolytic hydrogen.

H2O → ½ O2 + H2

Conversely, during a time of input energy deficit, this process is reversed and the hydrogen produced earlier is reconverted to electrical energy through a fuel cell.◦ Anode Reaction: 2H2 + 2O–2 → 2H2O + 4e–◦ Cathode Reaction: O2 + 4e– → 2O–2

WHAT IS HYDROLYSIS??

Energy density of H2 is ≥1k times larger than the upper limit of battery storage capacity.

Hydrogen can be used as a fuel for portable (vehicles) or stationary energy generation.

Totally void of Carbon emissions . Scientist James Barber of Imperial College

London hailed this as “enormous implications for the future prosperity of humankind.”

Why hydrolysis method

Inspired by photosynthesis to develop photoelectrolysis. Sunlight to split water.

Catalyst consisting of cobalt metal, phosphate and an electrode, placed in water.

Works at room temperature, in neutral pH water, and easy to set up.

The cobalt oxygen-evolving catalyst (Co-OEC) can use an energy input from a photoanode or photovoltaic.

Cobalt Phosphate Catalyst

Solar Energy splitting water into hydrogen and oxygen for fuel_ Daniel Nocera, MIT [MIRROR].flv

video

• The hydrogen will be stored in two 0.47 cubic meter(125 gallon) propane tanks, and the oxygen will be stored in one propane tank.

• The produced hydrogen gas is pressurized by the electrolyzer to its maximum rated pressure.

• Hydro-electrical power from dams, wind-energy and solar energy sources can all be fitted with hydrogen electrolysis units in order to produce enough hydrogen.

Storage of hydrogen

No greenhouse gases emitted. Zero emission in vehicles. Calorific value is

Hydrogen as a fuel

Tanks are repeatedly fast-filled using real gas and emptied slowly for testing.(cycle test)

The tank is monitored for permeation rates at 700 bar pressure.(permeability test)

Hydrogen sensors for testing leaks.

Safety measures & Limitations

Hydrogen storage testing at European Commission Joint Research Centre-Institute of energy.

Make hay while the sun shines.

Then use thestored hydrogen

to produce heat and

electricity on demand,day or night!

Matthew W. Kanan, Yogesh Surendranath and Daniel G. Nocera Chem. Soc. Rev., 2009, 38, 109-1 14

How to Store Excess Electricity by Jon r. Luoma Yale Env. 360,2010

Report of basic energy sciences published by office of science ,US department of energy.

Summary of electrolytic hydrogen production, NREL, September 2004 Hydrogen Safety in Storage and Transport, Pietro

Moretto ,European Commission Joint Research Centre

References